Signature gathering machine with disc separator

ABSTRACT

An improved flatwise gathering machine for signatures having a vertical stack of signatures in a supply hopper, there being a horizontal rotating separator disc an edge portion of which is shaped to perform the dual function of deflecting the leading end portion of the bottom signature in the hopper downwardly into the grip of jaws on a transfer drum and simultaneously relieving the weight on the bottom signature by elevating the front of the balance of the stack in the hopper. The cam disc has a mounting flange which receives either of two alternative signature separator adapters, one of which is especially constructed for use with signatures formed in a jaw folder and the other of which is particularly constructed for use with signatures formed in a former board folder.

United States Patent 1 Swanson SIGNATURE GATHERING MACHINE WITH DISCSEPARATOR [75] Inventor: Kermit E. Swanson, Naperville, ll].

[73] Assignee: R. R. Donnelley & Sons Company,

Chicago, Ill.

[22] Filed: Nov. 26, 1971 [21] Appl. No.: 202,152

[52] US. Cl. 271/101 [51] Int. Cl. B65h 3/08 [58] Field of Search271/41, 29; 270/56, 270/54 [56] References Cited UNITED STATES PATENTS3,650,525 3/1972 Hageman 271/29 1 3,768,804 Oct. 30, 1973 PrimaryExaminer-Richard E. Aegerter Att0rneyAxel A. Hofgren et al.

[57] ABSTRACT An improved flatwise gathering machine for signatureshaving a vertical stack of signatures in a supply hopper, there being ahorizontal rotating separator disc an edge portion of which is shaped toperform the dual function of deflecting the leading end portion of thebottom signature in the hopper downwardly into the grip of jaws on atransfer drum and simultaneously relieving the weight on the bottomsignature by elevating the front of the balance of the stack in thehopper.

The cam disc has a mounting flange which receives either of twoalternative signature separator adapters, one of which is especiallyconstructed for use with signatures formed in a jaw folder and the otherof which is particularly constructed for use with signatures formed in aformer board folder.

9 Claims, 17 Drawing Figures Patnted Oct. 30, 1973 3,768,804

5 Sheets-Sheet 1.

Patented Oct. 30, 1973 5 Sheets-Sheet 2 Patented Oct. 30, 1973 3,768,804

5 Sheets-Sheet 3 Patented Oct. 30, 1973 3,768,804

5 Sheets-Sheet 4 FIGJO Patented Oct. 30, 1973 3,768,804

FIG. I3 f i FIG 15 205 SIGNATURE GATHERING MACHINE WITH DISC SEPARATORBACKGROUND OF THE INVENTION The present invention constitutes animprovement upon the type of signature flatwise gathering machinedisclosed in Kleineberg et al. US. Pat. No. 2,621,039, issued Dec. 9,1952. l

The gathering machine of that patent has a cam actuated arrangement ofcooperating fingers which swing in and out of the corner area of a stackof signatures in the hopper of a gathering machine, and the fingers arecam actuated so that when they are swung into the stack corner areabetween the bottom signature in the stack and the next signature aboveit, one of the fingers is pivoted downwardly to bend down the corner ofthe bottom signature while the other. finger is pivoted upwardly toelevate the balance of the stack and relieve the pressure on the bottomsignature.

The foregoing mechanism of US. Pat. No. 2,621,039 requires a rathercomplex mechanical linkage system, and lacks any easy means forconverting a particular supply box of a gathering machine for usealternatively with jaw formed signatures or signatures formed on aformer board. In view of the fact that many printing plants whichproduce patent bound books may have both kinds of signatures going intoa single book, and with different runs having signatures of thedifferent types in different positions, it is important to be able toconvert any box of a flat gathering machine quickly from handling onetype of signature to handling the other type.

SUMMARY OF THE INVENTION In Kleineberg et al. US. Pat. No. 2,621,039 thesignature separating mechanism is particularly illustrated in FIGS. 7 to10, and that mechanism is operated from a control cam 145 having agroove 147, a cam follower 148 on a follower arm 150, a link 152, a rockarm 154, a rock shaft 96, a rocking link 156 on the rock shaft 96, and apush rod 143 the connection of which with the separator fingers is bestseen in FIGS. 8 and 9.

As seen in FIGS. 7 and 8, the fingers C and D swing in and out of thecorner of the stack of signatures in the supply hopper, and the finger Cthen pivots down to bend down the leading end portion ofthe bottomsignature while the finger D pivots up to relieve weight on the bottomsignature by elevating the front of the balance of the stack. A suctionmeans first pulls down the corner of the bottom signature to make roomfor the separator fingers to override said corner.

The improvement of the present invention utilizes a single rotating camseparator disc having a lower face which is shaped to deflect theleading end portion of the bottom signature down and an upper face whichis shaped to elevate the front of the balance of the stack and thusrelieve the weight on the bottom signature. The rotatable cam disc isoperated by a simple chain drive directly off the shaft 196 whichcarries the rotary drum signature extractor E, seen in FIG. 1 of thedrawings of US. Pat. No. 2,621,039. This eliminates the control cam 145and the entire complex linkage system which is necessary to operate theseparator fingers C and D.

In addition, jaw formed signatures have their open edges at the frontand a separator must penetrate the stack from the side, while formedboard signatures board signatures.

The separator cam disc of the present invention may be converted tohandle either type of signature merely by removing a one-piece adaptermember of one shape and substituting one of another shape.

THE DRAWINGS FIG. 1 is a fragmentary side elevational view of onesignature gathering box of a flatwise gathering machine embodying theinvention;

FIG. 2 is a fragmentary plan view of the apparatus provided with aseparator disc for jaw formed signatures, the location of a stack ofsignatures being illustrated in dot-dash lines;

FIG. 3 is a schematic view similar to FIG. 2 but showing only theseparator disc, signatures and suction grippers immediately before thedisc penetrates the stack;

FIG. 4 is a view similar to FIG. 3 with the separator disc in theposition it occupies substantially at the time the bottom signature isengaged by the jaws on the transfer drum;

FIG. 5 is a front elevational view of the apparatus;

FIC. 6 is a fragmentary side elevational view on an enlarged scale takensubstantially as indicated along the line 66 of FIG. 3;

FIG. 7 is a view similar to FIG. 6 but taken along the line 7-7 of FIG.4;

FIG. 8 is a top plan view of the separator disc and adaptor for jawformed signatures;

FIG. 9 is a sectional view taken substantially as indicated along theline 99 of FIG. 8;

FIG. 10 is a fragmentary view similar to FIG. 8 illustrating the jawformed signature adapter removed from the separator disc;

FIG. 11 is a fragmentary perspective view on an enlarged scaleillustrating the jaw formed signature adapter;

FIG. 12 is a fragmentary sectional view taken substantially as indicatedalong the line l2l2 of FIG. 11;

FIG. 13 is a top plan view of the adapter for former board signatures;

FIG. 14 is a fragmentary top plan view of the separator disc with theformer board signature adapter mounted thereon and the position of astack of signatures illustrated in dot-dash lines so as to show therelationship between the separator disc and the signatures insubstantially the same way as illustrated in FIG. 7 for the disc withthe jaw formed signature adapter;

FIG. 15 is a section on an enlarged scale taken substantially asindicated along the line 15-15 of FIG. 13 with the separator discillustrated in dot-dash lines;

FIG. 16 is a fragmentary sectional view taken substantially as indicatedalong the line 16-16 of FIG. 13; and

FIG. 17 is a view similar to FIG. 14 but illustrating the separator discand former board signature adapter immediately prior to penetration ofthe signature stack by the separator disc.

DETAILED DESCRIPTION OF THE INVENTION For the general structure of thegathering machine, and the drive for the series of individual boxes, orstations thereof, reference is made to US. Pat. No. 2,621,039. Referringto the drawings of the present application in greater detail, andreferring first to FIGS. 1, 2, and 5, a base frame, indicated generallyat 20, which includes an upright rear support 21, a central support 22and a forward support 23 connected by a horizontal web 24, a platform 25surrounding the upright support 21 and 22, and a line of forwardlyextending webs 26 which support the gatherer means, indicated generallyat 27. The latter means include a horizontal signature supporting panel28a and an inclined signature supporting panel 28b which supportgathered signatures S as they are moved along the machine by a gathererchain, indicated generally at 29. The gatherer structure 27 extendscontinuously along beneath a series of signature boxes, or stations,such as the station indicated generally at 30 in FIGS. 1, 2 and 5.

Each of the stations 30 includes a pedestal base 31 on which issupported an upstanding hollow housing 32. A hearing sleeve 33 extendsthrough the housing from its rear to its front and has an integralexternal flange 34 which bears against the rear of the housing and abracket plate 35 embraces the forward portion of the sleeve 33 and issecured to the front of the hollow housing 32 by bolts 36. I

Signature transfer drum means, indicated generally at 37, includes atransfer drum 38 which is seen in FIG. 5 to be keyed to a shaft 39 thatis journalled in the sleeve 33. At the rear of the shaft 39 is anenlarged hub 40 carrying a sprocket 41 by means of which the shaft 39and drum 38 are rotated through a drive chain 42 which corresponds tothe chain 221 illustrated in FIGS. 18 and 19 of 11.5. Pat. No.2,621,039.

The signature transfer drum 38 is provided with two sets of signaturegripping transferjaws 43 which are cyclicly opened and closed by cams asdescribed in detail in US. Pat. No. 2,621,039. The gathering station 30also includes mechanical sensing means, indicated generally at 44, whichcorresponds precisely to the detecting means H of US. Pat. No. 2,621,039and which is cam operated in the same way.

A signature supply hopper, indicated generally at 45, includes asignature supporting platform 46, a forward signature confiningassembly, indicated generally at 47, having a fore and aft movablecarrier bar 48 provided with upright posts 49 for signature confiningpads 50. A fixed rear signature guide 51 is positioned opposite theconfining pads so that a stack of signatures S, the outline of which isindicated by broken lines in FIG. 2, is confined between the pads 50 andthe guide 51. A fixed guide plate 52 is mounted upon a bracket 53 inposition to be contacted by the leading ends of signature S in hopper 45which form an exposed side of the stack, and an adjustable signatureconfining plate 54 is adjacent the trailing ends of the signatures inthe hopper. The above described signature supply hopper 45 differs onlyin detail from that in the US. Pat. No. 2,621,039.

Suction separator means, indicated generally at 55, includes a pair ofsuction separator heads 56 carried on a tube 57 which forms a Tconnection with a fore and aft extending tube 58 that is journalled inpillow blocks 59 and 60 so that it may be rocked to raise and lower thesuction heads 56. In order to rock the tube 58 it is provided with anarm 61 that is connected to a vertical push rod 62 which is cam actuatedin a manner generally similar to that disclosed for the suctionseparator means B of US. Pat. No. 2,621,039.

As heretofore described, the apparatus is either identical with thatdisclosed in US. Pat. No. 2,621,039 or mechanically modified inaccordance with commercial signature flatwise gathering machinesmanufactured and sold by the Sheridan Company, assignor of US. Pat. No.2,621,039. The novel structure of the present invention is that which ishereinafter described in detail.

Surmounting the hollow housing 32 is a generally rectangular open frame63 at the forward end of which is a split clamp 64 having a clampingbolt 65 to fixedly secure an upstanding stud 66. .lournalled on the stud66 is a separator disc assembly, indicated generally at '67, and fixedlysecured to the top of the disc assembly 67 is a drive pulley 68. Alsomounted in the rectangular open frame 63 is a gear box 69 having anupright output shaft 70 provided with a pulley 71, and a drive belt 72is trained around the pulleys 68 and 71. The gear box 69 also has aninput shaft 73 which is connected by a coupling 74 with a shaft 75 thatis journalled in a bearing block 76 mounted on the rear end of the openframe 63; and the shaft 75 projects rearwardly to fixedly receive asprocket 77.

Mounted on the hub 40 which carries the drive sprocket 41 for thetransfer drum 38 is a separator drive sprocket 78, and a drive chain 79which is trained around the sprocket 78'and the sprocket 77 A bracket 80mounted on the outer end of the open frame 63 adjustably supports a stubshaft 81 on which is journalled a tensioning sprocket 82 for the drivechain 79.

Referring now particularly to FIGS. 3, 4 and 6 to 12, the disc separatorassembly 67 includes a mounting element 83 and an adaptor element 84which is best seen in FIGS. 8 to 11 to be secured to a relatively thinfastening flange 85 on the mounting element 83 by means of machinescrews 86, which impale a mounting flange 87 on the adaptor element andfastening flange 85. The total thickness of the mounting flange and thefastening flange is seen to equal the thickness of the mounting element83.

As best seen in FIGS. 3 and 4, the mounting element 83 includes a bodyportion 88, the radius of which from an axial hole 89 is greater thanthe distance from the hole and the stud 66 to the leading edge L of asignature S in the supply hopper 45. At the side opposite the area 88,the mounting element has a clearance portion 90 of substantially smallerdiameter which is seen in FIGv 3 to clear the leading edge L ofasignature. As indicated by the arrow in FIG. 3, the separator discassembly 67 rotates clockwise, and the fastening flange 85 occupies therim of the trailing part of the clearance portion 90. As best seen inFIGS. 9 and 12, the periphery of the body portion 88 immediatelytrailing the clearance portion 90 is provided with a downwardlyprojecting bottom cam lug portion 91 and an upwardly projecting top camlug portion 92 which overlies the portion 91. The leading ends of thecam lug portion 91 and 92 are contiguous with a radially extending face93 which constitutes the leading end of the body portion 88 and the lineof demarcation between that portion and the clearance portion 90. Theface 93 is seen in FIG. 12 to include a lower portion 94 which isperpendicular to the top surface of the body portion 88, and to alsoinclude a surface 95 which is inclined rearwardly in a trailingdirection and occupies approximately one-half the thickness of the bodyportion and extends to the top surface of the top cam lug portion 92. Asseen in FIGS. 8 and 9, the top and bottom cam lug portions 91 and 92have inclined trailing ends 91a and 92a, respectively.

The adapter element 84 includes a body portion 96 which has the mountingflange 87 along its inner edge portion, and the body portion 96 has aleading edge which is radial across the width of the mounting flange andwhich then has a leading face 97 at a negative rake angle. Along theperiphery of the adapter element 84 are a bottom cam lug 98 and a topcam lug 99; and the trailing end of the adapter element 84 has surfacescomplementary to the surfaces 94 and 95 at the leading end of themounting element body portion 88.

As best seen in FIGS. 9, 11 and 12, the bottom cam lug 98 includes acircumferential outer surface 100 which is inclined radially inwardly atabout a 45 angle, and the bottom cam lug has an inclined leading surface101 which is at an angle between about 25 and 30 to the horizontal andmargins which diverge from a rounded nose 102 circumferentially to amaximum radial width 103 from which it tapers in an area 104 to theinner edge of the inclined outer surface 100. Thus, the inclined leadingsurface 101 is of generally an elongated diamond shape with a roundednose and a long tapering trailing end. The top cam lug 99 is best seenin FIG. 12 to have an inclined leading surface 105 which forms an angleof about to the horizontal and trails the inclined leading surface 101of thebottom cam lug by a short distance.

The cam lug portions 91 and 92 of the mounting element 83 provideuninterrupted continuations of the bottom and top cam lugs 98 and 99,respectively.

A comparison of FIGS. 2 and 4 shows that a chord from the rounded nose102 of the bottom cam lug 98 to the inclined trailing surfaces 91a and92a of the cam lug portions 91 and 92 is longer than the width of thetransfer drum 38.

In operation, the suction members 56 and the cam separator disc 67operate in timed relationship with the rotation of the transfer drum 38as follows. The suction tube 58 is pivoted to swing the suction heads 56upwardly into contact with the corner portion C of the lowermostsignature S1 as seen in FIG. 6, and suction is simultaneously applied sothat when the suction heads 56 are rocked downwardly to the position ofFIG. 7 they will bend down the corner area C of the bottom signature S1.This occurs as the cam separator disc asembly 67 is approaching theposition of FIGS. 2 and 3, so that the rounded nose 102 of the adapterelement 84 may penetrate the stack of signatures S in the hopper betweenthe bottom signature S1 and the next higher signature S2. As the camdisc assembly 67 rotates to the position of FIG. 4, it bends down theentire leading edge portion of the bottom signature S1 to a positionwhere it may be gripped by the jaws 43 on the transfer drum 38 whichwithdraws the bottom signature S1 from the stack in the hopper andtransfers it to the gathering assembly 27 where it is associated withother signatures S from other feeding stations 30 and carried along bythe chain means 29. As the bottom cam lug 98-91 bends down the bottomsignature S1 the top cam lug 99-92 supports and slightly lifts thesignature S2 and all those above it so as to relieve weight on thesignature S1 and facilitate its removal from the hopper by the transferdrum jaws 43.

6 The adapter element 84 seen in FIGS. 2 to 12 is of the type which isadapted for use with jaw formed signatures that have an open leading endand a closed side margin. Accordingly, the periphery of the adapterele-' ment 84 forms an arc of a circle about the axis of the discseparator 67, and the rounded nose 102 is thus positioned to penetratethe side margin of the stack of signatures as seen in FIG. 3. Ifitpenetrated the open leading end, it might penetrate between the pages ofthe signature and thus cause a malfunction of the apparatus bypresenting only a part of the signature to the jaws 43.

Referring now to FIGS. 13 to 17, the mounting element 83 is illustratedin conjunction with an adapter element 184 which is constructed for usewith signatures which have been folded on a former board. As previouslyindicated, such signatures have a closed leading end and an open margin;so that a separator disc must penetrate the stack between the bottomsignature and thenext signature at the leading end L rather than at aside margin.

In order to accomplish this, the adapter element 184, which has amounting flange 187 for attachment to the fastening flange of themounting element 83, has a periphery which is an arc of a circle aboutthe axis of the separator disc from its trailing end to the point p inFIG. 17; and from that point to a rounded leading end 202 the periphery184a of the adapter element 184 is an arc of constantly decreasingradius. A leading surface 197 of the adapter element 184 is quite shortand concavely curved with respect to the direction of rotation ofthedisc, and whereas the adapter element 84 has a leading surface 97 whichis perpendicular to the plane of the disc, the leading surface 197slopes in a trailing direction with a. slightly convex curve.

The adapter element 184 has a bottom cam lug 198 and a top cam lug 199which are generally similar to those of the adapter element 84, butwhich taper inwardly toward the rounded nose 202 because of theconstantly descreasing radius of the peripheral surface area 184a of theadapter element 184. Likewise, because of the blunter shape of therounded nose 202 as compared with the rounded nose 102, an inclinedleading surface 201 of the bottom cam lug 198 is more of a tear dropshape than'an elongated diamond.

Like the adapter element 84, the adapter element 184 has its bottom camlug 198 provided with a circumferential outer surface which is inclinedradially inwardly about 45, and the inclined leading surface 201 of thebottom cam lug is at an angle between about 25 and 30 to the horizontal.Likewise, the top cam lug 199 has a leading surface 205 which isinclined to the horizontal at an angle of about 20 and which trails theinclined leading surface of the bottom cam lug by a short distance.

In use, the separator disc equipped with the adapter element 184cooperates with the suction separator cups 56 and the transfer drum jaws43 in the same way as does the disc equipped with the adapter element84. The only difference is in the fact that the adapter element 184penetrates the stack from the leading end L instead of from a sidemargin.

The foregoing detailed description is given for clearness ofunderstanding only and no unnecessary limitations should be understoodtherefrom, as modifications will be obvious to those skilled in the art.

I claim:

1. In a signature gathering machine of the type which has a line ofsignature supply hoppers each containing signatures stacked adjacent oneanother with their edges forming an exposed side of the stack, conveyormeans adapted to receive and accumulate signatures from said hoppers,signature transfer means operatively associated with each hopper todeliver successive endmost signatures from the forward end of the stackto the conveyor, and suction means to bend a corner of the exposed edgeportion of the endmost signature in the stack forwardly away from thebalance of the stack to provide a gap, improved separator means forpenetrating the gap to deflect the bent away edge portion of the endmostsignature into the transfer means for separation from the stackcomprising, in combination:

a shaft adjacent and parallel to the exposed side of the stack ofsignatures;

means for rotating said shaft;

and a transverse separator disc on said shaft which occupies a planeimmediately forward of and parallel to the forward end of the stack,

said disc having a body with generally planar front and rear faces, saidbody having a radially narrow clearance portion which clears the exposedside of the stack and the circumferential extent of which is greatenough-that the disc is clear of the stack during a part of eachrevolution,'said body also having a radially extended transverselyarcuate separator portion which trails the clearance portion as the discrotates and penetrates the gap behind the forwardly bent corner of theendmost signature,

said separator portion including a peripheral circumferential front camlug which projects forwardly from the planar front face and has aninclined leading surface,

and a peripheral circumferential rear cam lug which projects rearwardlyfrom the planar rear face generally in register with the front cam lugand has an inclined leading surface which joins that of the front camlug along a rounded nose, so that the leading end of the separatorportion is generally wedge shaped in cross section and extends forwardlyand rearwardly from the plane of the disc, said cam lugs wedging betweenthe bent endmost signature and the balance of the stack to deflect thebent away edge portion of the endmost signature into the transfer meansand substantially simultaneously move the forward portion of the balanceof the stack toward the rear to relieve pressure at the endmostsignature.

2. The combination of claim 1 in which the front cam lug includes acircumferential outer surface which is inclined radially inwardly atabout 45, and in which the inclined leading surface of said front camlug is at an angle between about 25 and 30 to the plane of the body andhas margins which diverge from a rounded nose circumferentially to amaximum radial width from which it tapers to the inner edge of saidinclined outer surface. 1

3. The combination of claim 2 in which the inclined leading surface ofthe rear cam lug trails the inclined leading surface of the front camlug by a short distance.

4; The combination of claim 3 in which the inclined leading surface ofthe rear cam lug is at an angle of about 20 to the plane of the body.

5. The combination of claim 1 in which the separator disc comprises amounting element axially carried on the shaft, said mounting elementincluding the entire clearance portion and having trailing parts of eachof the lugs integral therewith, and there being a fastening flangeextending from the trailing end of the clearance portion to the vicinityof said integral lug parts, and an adapter element detachably secured tosaid flange, said adapter element having the leading parts of both lugsformed thereon, said leading lug parts and said trailing lug parts beingcontinuous.

6. The combination of claim 5 in which the leading end of the adapterelement is shaped and positioned to penetrate the gap from a side marginof the endmost signature 7. The combination of claim 1 in which theleading ends of the lugs are shaped and positioned to penetrate the gapfrom a side margin of the endmost signature.

8. The combination of claim 7 in which the front cam lug includes acircumferential outer surface which is inclined radially inwardly atabout 45, and in which the inclined leading surface of said front camlug is at an angle between about 25 and 30 to the plane of the body andhas margins which diverge from a rounded nose circumferentially to amaximum radial width from which it tapers to the inner edge of saidinclined outer surface.

9. The combination of claim 1 in which the leading ends of the lugs areshaped and positioned to penetrate the gap from the leading edge of theendmost signature.

1. In a signature gathering machine of the type which has a line ofsignature supply hoppers each containing signatures stacked adjacent oneanother with their edges forming an exposed side of the stack, conveyormeans adapted to receive and accumulate signatures from said hoppers,signature transfer means operatively associated with each hopper todeliver successive endmost signatures from the forward end of the stackto the conveyor, and suction means to bend a corner of the exposed edgeportion of the endmost signature in the stack forwardly away from thebalance of the stack to provide a gap, improved separator means forpenetrating the gap to deflect the bent away edge portion of the endmostsignature into the transfer means for separation from the stackcomprising, in combination: a shaft adjacent and parallel to the exposedside of the stack of signatures; means for rotating said shaft; and atransverse separator disc on said shaft which occupies a planeimmediately forward of and parallel to the forward end of the stack,said disc having a body with generally planar front and rear faces, saidbody having a radially narrow clearance portion which clears the exposedside of the stack and the circumferential extent of which is greatenough that the disc is clear of the stack during a part of eachrevolution, said body also having a radially extended transverselyarcuate separator portion which trails the clearance portion as the discrotates and penetrates the gap behind the forwardly bent corner of theendmost signature, said separator portion including a peripheralcircumferential front cam lug which projects forwardly from the planarfront face and has an inclined leading surface, and a peripheralcircumferential rear cam lug which projects rearwardly from the planarrear face generally in register with the front cam lug and has aninclined leading surface which joins that of the front cam lug along arounded nose, so that the leading end of the separator portion isgenerally wedge shaped in cross section and extends forwardly andrearwardly from the plane of the disc, said cam lugs wedging between thebent endmost signature and the balance of the stack to deflect the bentaway edge portion of the endmost signature into the transfer means andsubstantially sImultaneously move the forward portion of the balance ofthe stack toward the rear to relieve pressure at the endmost signature.2. The combination of claim 1 in which the front cam lug includes acircumferential outer surface which is inclined radially inwardly atabout 45*, and in which the inclined leading surface of said front camlug is at an angle between about 25* and 30* to the plane of the bodyand has margins which diverge from a rounded nose circumferentially to amaximum radial width from which it tapers to the inner edge of saidinclined outer surface.
 3. The combination of claim 2 in which theinclined leading surface of the rear cam lug trails the inclined leadingsurface of the front cam lug by a short distance.
 4. The combination ofclaim 3 in which the inclined leading surface of the rear cam lug is atan angle of about 20* to the plane of the body.
 5. The combination ofclaim 1 in which the separator disc comprises a mounting element axiallycarried on the shaft, said mounting element including the entireclearance portion and having trailing parts of each of the lugs integraltherewith, and there being a fastening flange extending from thetrailing end of the clearance portion to the vicinity of said integrallug parts, and an adapter element detachably secured to said flange,said adapter element having the leading parts of both lugs formedthereon, said leading lug parts and said trailing lug parts beingcontinuous.
 6. The combination of claim 5 in which the leading end ofthe adapter element is shaped and positioned to penetrate the gap from aside margin of the endmost signature.
 7. The combination of claim 1 inwhich the leading ends of the lugs are shaped and positioned topenetrate the gap from a side margin of the endmost signature.
 8. Thecombination of claim 7 in which the front cam lug includes acircumferential outer surface which is inclined radially inwardly atabout 45*, and in which the inclined leading surface of said front camlug is at an angle between about 25* and 30* to the plane of the bodyand has margins which diverge from a rounded nose circumferentially to amaximum radial width from which it tapers to the inner edge of saidinclined outer surface.
 9. The combination of claim 1 in which theleading ends of the lugs are shaped and positioned to penetrate the gapfrom the leading edge of the endmost signature.